Conduit-stopper.



Nm 798,03l. PATENTED AUG.. 22, 1905.

W. D, GHERKY. y

CONDUIT STOPPER.

APPLICATION PILED Nov. 19, 1904.

W/ TNESSES:

i be a serious matter in many places.

AUNITED STATES PATENT orrron CONDUIT-STOPPER.

Specfication of Letters Patent.

Patented .Aug. 22, 1905.

Application filed November 19, 1904. Serial No. 233,490.

' To all whom it may concern:

Be it known that I, WILLIAM D. GHERKY, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State ot' Pennsylvania, have invented certain new and useful Improvements in Conduit- Stoppers, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to means for temporarily stopping ducts or tubes, and has for its purpose the production of means particularly adapted to plug or stop the ends of conduitducts for electrical and other purposes, either in the trenches during the progress of laying or in the manholes after the conduits are completed and before the cable is installed therein.

The invention is applicable to ducts installed either in buildings or underground, but is intended for use principally in the latter and therein to work in process of Construction.

Heretofore it has been customary to stop the ends of conduit-ducts by means of wooden plugs cut to fit approximately and then driven into place. Such a method is unsatisfactory, however, both because it is ineficient for the purpose intended and because there is always a liability of fracture of the conduit. When ducts are left exposed at points where work is temporarily stopped, as at night or during rain-storms, they must be closed in some way to prevent the entrance of water with its attendant mud or silt, stones, chips, and other foreign substances which might interfere with the drawing in of cable by partly or wholly obstructing the tubes. A wooden plug never fits a dnct perfectly, so as to prevent the entrance of water, even if wrapped with paper or cloth, unless it is driven in, and then when the wood is moistened it swells with great danger of its directly splitting the duct or of breaking the same in unplugging. One reason for this lack of fit is that the ducts are commonly made of burnt clay and vary somewhat in size, while the plugs are too hard and inelastic to accommodate themselves to the variations. Hence they must be driven in, and if not so driven they are apt to fall out, leaving the tubes unstop'ped. It is impossible to keep children or the curious out of trenches in which the ends of the ducts are exposed and racked back like steps, and the knocking out of the plugs is so common as .to

without saying that where the tubes are thus;

leakage.

It goes left unplugged in storms a certain amount of lthe work must always be ripped out and reaid.

In order to overcome the objections stated and to prevent mischievous or accidental displacement of the closures, 1 have devised my improvedconduit-stopper, whereby not only is Water absolutely eXcluded from the ducts, but a tool is required to unstop the ends, and only authorized persons can interfere with the closures.

Briefly stated, my invention comprises a double seal with sufficient length of stern to act as a guide for centering and steadying, double assurance being thus given against The seal is obtained by the use of fleXible disks of a diameter somewhat larger than that of the ducts to be stopped, clamped at opposite ends of a stern carrying a bail or ring at each end, by which the entire device can be hooked out by the pipe layer when he commences work.

While particularly adapted to stopping conduits, my invention is adaptable to many other kinds of tubes, and I do not wish to limit myself, therefore, to this usc only, although for convenience I shall limit my description' thereto.

'My invention is illustrated in the accompanying drawings wheren- Figure 1 is a sectional View of the end of a dnct with the double-seal stopper inserted therein, while Figs. 2 and 3 are detail views showing modifications in fastenings and bails.

In the drawings, A represents the end of a duct of burnt clay, supposed to be laid in a trench or terminating a line of conduit at a manhole with the end open. Within the duct is shown the double-seal stopper B, wherein lies my invention. It comprises the seal proper, consisting of two fiexible disks b b and the stern b with terminal bails or rings b' b'. The disks 6 are made of a diameter slightly greater than that of the duct, so that when inserted therein each disk will have its periphery compressed to bow the center out or dish the disk. Each disk is clamped on the stern b between a pair of washers b IP, underlying corresponding nuts 6 6 threaded on the ends of the stern. Between the outer nut and Washer at each end is clamped the cross member or bar of the bail b', and outside the nuts 6 the ends of the stem are provided with cotter-pins b* to keep the nuts from coming oif.

" directly on the outer face of the disk, the

other features of Construction remaining the same as in Fig. l. In Fig. 3,`on the other hand, the bar of the bail remains ofi' the surface of the disk, as in Fig. 1; but a circular plate or disk of metal ?2 is provided, which rests on the surface of the disk and clamps the same against the Washer b on the other side. Each of these constructions has its advantages the first particularly for square ducts and the second where the disks employed are thin or worn. The bar of the bail in Fig. 2 can be made of any width or shape to cover as much or as little of the surface of the disk as required.

The operation of my invention is simple. When a tube or duct is to be stoppered, the instrument B is inserted from the end with some force and pushed in to a point beyond reach of the unaided hand of a malicious person. As the disks are forced into the duct they dish out, as shown in Fig. 1, and exert considerable peripheral pressure against the inner Walls of the duet. This is rendered more eflicient in keeping out the water or silt, or what not, by the fact that the convexity of each dish is inward, so that any Water-pressure against the surface acts to increase the tightness of the seal. The double seal not only renders the closure more certain, but the stem being thereby centered the disks 6 are kept With their planes perpendicular to the aXis of the duct, which is an indispensable requisite for successful operation, as otherwise the convexing or dishing out of the seals would not act uniformly and With eertainty. hen it is desired to remove the seal or closure, the pipo layer insertsa long rod with a terminal hook and catching the hook in one of the bails b' simply hooks the device out. The first effort at Withdrawal, owing to the reverse dish of the seals, is very difficult, the peripheral edge of each disk being forced backward against the resistance of friction with the inner Wall of the duct, which has a tendency to turn the disk edges and reverse the dishing. This scraping against the walls in hooking out, however, is a very valuable feature in itself, as it provides absolutely for cleaning out the duet without having to attend to it after unstopping. All water, mud, silt, stones, sticks, or other articles in the end of the duct outside of the seal are scraped out as it is withdrawn, first by the outer disk in bulk and then by the inner disk as a follower or gleaner of remnants. The surface of the duct inside is left in practice as clean as when newly taken from the kiln, and the disks do not turn in withdrawin'g, as a rule, until they are pretty well worn, when the large disk 6 of Fg. 3 may be employed to reinforce them.

It is to be observed that having provided the stem or rod b and its fittings this device can be adapted to all sizes and shapes of conduit by merely providing avariety of disks. For instance, in changing from a three-inch round duet to a four-inch round duet it is merely necessary to change the size of disk 6 employed. When employng the accustomed wooden plugs, on the contrary, a complete set of each diameter must be carried, and as the ducts are not uniform these plugs of each size must be subdivided into large and small. When the disks ?9 take up a permanent concave set from continued use in the same direction, it is simply necessary to reverse them in the clamps to regain the advantage of free dishing.

In storing these tools, which are simple to handle, they are taken apart, the disks made up into piles, and the rods and bails packed in boxes. A convenient manner of handling the disks is to string them on wires or spindles. One set of irons serves for all sizes of duct and all shapes. Hence the only material to be kept in variety and quantity is the disk Stuff.

The cost of these tools is slightly more than for the wooden plugs, but not so much as that plus labor in fitting and the cost of breakage, &0. Neither is it so much as the cost of empty cement-bags, most frequently used for wrappings when plugs do not fit, and the limited number of irons required makes the total first cost smaller than the total first cost of an outfit of the old type of suflciently comprehensive character to do the same work. I mention these facts to show the saving elfected by the use of the separable feature, the invention having' solv'ed a serious problem in underground work which has never before been satisfactorily disposed of. q

Having thus described my invention, What I claim, and desire to secure by Letters Patent, is-

l. A Conduit-stopper comprising a plurality of flexible disks axially mounted on a spacingrod and reversibly insertible, and means at each end adapted to receive a removing-tool.

2. AConduit-stoppercomprisingaplurality of flexible disks, a spacing-rod on which the disks are mounted, said stopper being reversibly insertible in the conduit, and bails secured to the rod at either end adapted to receive a removing-tool.

3. AConduit-stoppercomprisingaplurality of flexible disks, a central spacing-rod removably connected to said disks, and bails removably Secured to said rod at either end, said stopper reversibly insertible in the conduit.

' 4:. A Conduit-stopper comprising a pair of flexible disks of greater diameter than the duet in which they are to be used, a central for removing said stopper from the duet, said stopper forming, When setup, a substantially cylindrical structure and When the parts are unassembled are resolved intosubstantially flat or plane figures for packing purposes.

In testimony Whereof I affix my signature in presence of tWo witnesses.

W ILLIAM D. GHERKY.

Witnesses:

JAMES J. MURPHY, JOHN J. MCDUFFEE. 

